Bit error rate (BER) is often utilized in communication systems as a convenient figure-of-merit for characterizing the performance of a communications link under various conditions. For example, a digital communication system may have a target BER of 10−5 (i.e. no more than 1 in 105 bits are received in error) but an actual BER measurement of 10−2 may indicate a need for troubleshooting or adjusting certain parameters of the system to achieve the target BER.
In high BER environments, synchronizing frames of test patterns (such as PN9) to measure the BER can be quite difficult because the synchronization systems can underperform. Classical BER calculation methods can require data to have consistent lengths. However, in circumstances where bit insertions and/or deletions are possible, these methods can fail to produce meaningful results. For example, if a single bit is inserted into the middle of an otherwise correct frame of 1024 bits, a simple bit comparison would yield ˜512 bit errors.
Many factors can contribute to BER degradation in satellite communications, including atmospheric turbulence, low elevation angles, intermodulation noise, interference from other transmitters, etc. It can be important to measure the BER of a communication link under various operating conditions and parameters to troubleshoot and/or optimize a satellite communication link, particularly when transmit power is limited.
One challenge associated with measuring BER includes a comparison of transmitted data vs. received data, which can require knowledge of the transmitted data and alignment with the received data. Many digital signal processing research publications and conference presentations begin with the statement: “assume the system is synchronized.” The issue is that systems do not necessarily start synchronized. A need exists for systems and methods that can be utilized to efficiently align portions of data streams.